Weft inserting apparatus for a warp knitting machine

ABSTRACT

A plurality of weft threads pass through a chain type of thread guide and are picked up by a tensioning chain for presentation to the magazine chain of a warp knitting machine. Weft thread is supplied by a plurality of spools located at one side of the machine. The thread guide comprises a single chain or a pair of chains arranged in the form of a figure &#39;&#39;&#39;&#39;8&#39;&#39;&#39;&#39;. The tensioning means is an endless chain equipped with gripping clip devices for taking the free end of the thread from the guide means and drawing it away therefrom. The angle of the direction of travel of the thread guide chain relative to the direction of travel of the chain of the tensioning means is such that the tensioning means draws the thread from the guide means at an angle of substantially 90* during the travel of the respective chains. In this fashion, the friction frequently associated with prior art devices is significantly reduced.

Kohl

[ Nov. 4, 1975 WEFT INSERTING APPARATUS FOR A WARP KNITTING MACHINE [76] Inventor: Karl Kohl, Chlorodont Str. 10,

Obertshausen, Germany, 6053 22 Filed: Mar. 27, 1975 21 App1.No.:562,407

[30] Foreign Application Priority Data 1/1974 Kamp 66/84 3/1974 Kohl 66/84 Primary ExaminerRonald Feldbaum Attorney, Agent, or FirmBehr & Woodbridge [57] ABSTRACT A plurality of weft threads pass through a chain type of thread guide and are picked up by a tensioning chain for presentation to the magazine chain of a warp Apr. 10, 1974 Germany 2417492 knitting machine w thread is Supplied by a l ity of spools located at one side of the machine, The 661/5; thread guide Comprises a Single chain or a pair f 6 n h i g d i th f f a fig 8 Th t [58] held of Search 66/84 84 A; sioning means is an endless chain equipped with grip- 28/1 in cli devices for takin the free end of the thread P g P g from the guide means and drawing 1t away therefrom. [56] References Clied The angle of the direction of travel of the thread guide UNITED STATES PATENTS chain relative to the direction of travel of the chain of 2,000,643 5/1935 Morton 66/84 A the tensioning means is Such that the tensioning means 2,743,596 5/1956 Noe 66/84 draws the thread from the guide means at an angle of ,769 9/1971 Walford... 66/84 A substantially 90 during the travel of the respective 3,636,731 1/1972 Jones 66/84 A chains In this fashion the friction frequently associ- 3,680,332 8/1972 Bassist 66/84 A ated with prior art devices is significantly reduced 3,703,818 11/1972 Umeda et al. .r 66/84 A 3,771,330 11/1973 Carman 66/84 A 5 Claims, 5 Drawing Figures v9 Aqc Vcl imiripl wnm US. Patent NOV.4, 1975 .Sheet10f3 3,916,649

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E 'Il o 3 PRIOR ART PRIOR ART U.S. Patent Nov. 4, 1975 Sheet 2 of 3 3,916,649

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US. Patent Nov. 4, 1975 Sheet 3 of3 3,916,69

WEFI INSERTING APPARATUS FOR A WARP KNITTING MACHINE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to warp knitting machines and more particularly to an improved weft inserting apparatus for use on warp knitting machines.

2. Description of the Prior Art There are several different types of weft inserting devices known to those of ordinary skill in the knitting machine art.

One type of known prior art device is described in U.S. Pat No. 3,364,701 to A. J. Carman. According to that apparatus, the spools of thread are attached to an endless moving chain which sucessively presents each individual weft thread to a pair of inwardly moving take-up chains which, in turn, present the thread to the warp knitting machine. One obvious disadvantage of such a device is that it is undesirable to have the spools in motion since, if there is weft breakage or the like, the whole weft inserting mechanism must be stopped.

Another typical prior art device is disclosed in German Patenschrift 2,034,286 in which the threads from a plurality of weft spools are fed to a tensioning chain via a plurality of specially shaped and moveable lever guides. One disadvantage of an approach such as this is that additional undesirable friction forces are exerted upon the threads due to the long length of the lever guides through which they must pass. There is also a certain amount of inertia associated with lever mechanisms and this, in turn, may exert undesirable forces upon the threads.

In order to reduce the friction associated with prior art weft inserters, a new technique was recently developed which incorporates a chain or a pair of chains in the form of a figure 8. Such an apparatus is fully disclosed in U.S. Pat. No. 3,703,818 issued to Umeda, et al. According to one embodiment of that invention, the chain is an endless chain in the shape of a figure 8. Approximately half of the length of the chain includes a plurality of hollow pins which carry each individual weft thread. An illustration of the endless type of chain thread guide as disclosed in the Umeda, et al patent is shown as prior art in FIG. 1. According to a second embodiment of the Umeda, et al. apparatus, the thread guide device comprises a pair of chains, one located above the other so as to form a Figure 8. Anillustration of this embodiment is shown in FIG. 2 as prior art. FIG. 3 shows the use of such prior art thread guides in the context of warp knitting machines. For the purpose of understanding this invention, the specification of the Umeda, et al. patent U.S. Pat. No. 3,703,818 is hereby incorporated by reference.

SUMMARY OF THE INVENTION According to the present invention, a plurality of weft threads are supplied to a thread guide from a plurality of weft supply spools. The thread guide comprises a single chain or a pair-of chains arranged in the form of a figure 8. Weft threads are passed from the continuous thread guide to a tensioning means comprising an endless chain equipped with gripping devices for taking the free end of the thread from the guide means and drawing it away therefrom. The thread guide is angularly displaced relative to the tensioning chain in such a fashion as to draw the thread out of the thread guide at an angle of approximately The tensioning chain thereafter presents one end of the thread to a first weft inserting chain. A second weft inserting chain grasps the second end of the thread from the thread guide apparatus. The weft threads are then presented to the warp knitting machine in a conventional fashion.

One important feature of the invention is the fact that it greatly reduces the thread abrasion formerly associated with weft inserting devices. The reduced abrasion is in large part attributable to the fact that the thread is drawn from the spools through the thread guide and to the tensioning chain in a relatively direct path. This is distinguishable from many prior art devices in which the path of the thread often had to round many corners and curves. By reducing the comers and curves associated with prior art thread paths, it was possible, by means of this invention, to avoid much unnecessary thread abrasion. This decreased thread abrasion, in turn, results in less thread breakage and greater overall machine efficiency.

Other features of the present invention will be more fully understood with reference to the following drawmgs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of a prior art thread guide according to the endless chain figure 8 variety.

FIG. 2 is a side elevation view of another prior art embodiment of a thread guide incorporating two chains arranged in theform of a figure 8.

FIG. 3 is a plan view of aprior art weft inserter incorporating the figure 8 type of thread guide.

FIG. 4 is a top plan view of the present invention shown in its entirety.

FIG. 5 is a side elevation view of the embodiment of FIG. 4.

DESCRIPTION OF THE INVENTION During the course of this description, like numerals will be used to indicate like elements according to the different drawings.

In order to better understand the invention, a short discussion of prior art elements and approaches will follow. The present invention is made possible in large part by the introduction into the industry of the figure 8 type thread guides such as those disclosed in U.S. Pat. No. 3,703,818 issued on Nov. 28, 1972 to Umeda, et al. which is hereby incorporated in toto by reference. FIG. 1 of this disclosureis substantially identical to FIG. 2 of U.S. Pat. No. 3,703,818. Simarlily, FIG. 2 of this disclosure is substantially identical to FIG. 8 of the same Umeda, et al. patent. One advantage of these figure 8 thread guides is that they can feed a plurality of weft threads to a warp knitting machine without causing the threads to become twisted. The figure 8 thread guides are able to avoid the twisting problem due to the fact that the twist imparted to the thread at the top of the figure 8 is reversed by the twist given to the thread at the bottom of the figure 8. While these devices are relatively new, nevertheless they are known to those of ordinary skill in the art.

While the figure 8 weft inserters of the sort disclosed in the Umeda, et al, patent have many distinct advantages, they still have associated with them a certain amount of undesirable thread abrasion due to the fact that the path of the thread from the spool to the thread guide is not a relatively straight and direct path. Referring, for example, to FIG. 1 of U.S. Pat. No.

3 3,703,818 it will be noted that interposed between the spools of weft thread and the thread guiding means is a special swing means for decreasing the frictional contact between threads. It will be noted that in such an embodiment, there is a sharp angle between the thread coming into the swing and the thread leaving the swing means. This additional angle is a source of undesirable abrasion. Likewise, the thread. going into the thread guide means subtends a substantial angle with the thread leaving the thread guide means. Such an arrangement is illustrated as prior art in FIG. 3 and corresponds generally to FIG. 1 of the Umeda, et al. patent.

The present invention according to a preferred embodiment thereof is illustratedin FIGS. 4 and 5. Ac-

cording to those figures, a pair of magazine type chains 1 and 2 of equal length are provided at either side of the machine. Chains 1 and 2 are shown disposed at an angle of 90 from their true orientation in order to better illustrate their function.

A plurality of needles 3 is likewise shown at approximately 90 from their true orientation for purposes of clearer illustration. Chains l and 2 are provided with a plurality of thread clips 7 of the sort known to those of ordinary skill in the art. The purpose of the clip 7 is to grip the weft threads 5 and in the case of chains land 2 to present them to the needles 3. Located at the opposite end of chains 1 and 2 from the needles 3 is a tensioning chain 4'likewise equipped with a plurality of thread clips 7. The tensioning chain 4 is disposed at an angle with respect to chains 1 and 2. The elements thus far described are known to those of ordinary skill in the art and arediscus sed in some detail in Patentschrift 2,034,283 the contents of which is hereby incorporated by reference.

Located at. oneside of the machine and shown in crosshatching is thread guide 6. Thread guide 6 is the relatively new figure 8 type of thread guide discussed in the Umeda, "at al. U.Sl Pat. No. 3,703,818. Thread guide 6 may comprise a single chain formed in the configurationof a figure 8 such as that illustrated as prior art in FIG. 1. Alternatively, thread guide 6 could be a pair of individual chains arranged one above the other in the form of a figure 8 such as that illustrated as priorart in FIG. '2, I

The weft threads 5 are supplied from a thread source or rack 9 which includes a plurality of rigidly mounted weft thread spools 10. Each spool 10 has associated with it a reserve spool which is attached thereto and which is automatically brought into supplying arrangement when the first spool is exhausted of thread.

In operation, the thread 5 supplied from spool 10 passes through thread guide 6 and is presented to one end of tensioning chain 4. The free-end of thread 5 is gripped by'thread clip 7 and drawn away from thread guide 6 in a manner illustrated in FIG. 4. Once the thread 5 has been drawn the distance between chains 1 and 2, the free end is picked up by a thread clip 7 on chain 2 and by another thread clip 7 on chain 1. The thread is then cut at the end close to chain 1 and presented in parallel fashion to the knitting needles 3. It is an important feature'of the present invention that the weft threads 5 stay in a substantially parallel relationship. It is another important feature of the present invention that the thread 5 is drawn out of thread guide 6 by tension chain 4 at an angle of substantially 90 with respect tothread guide 6. In this manner, the.. threads 5 describe a substantially direct and straight path from the spool 10 to the tensioning chain 4 thereby greatly minimizing the abrasion associated with causing thev thread to go around sharp curves or cor- In order to draw the thread 5 out of thread guide 6 at an angle of substantially it is necessary that the speed of the chain 6 be the same as the velocity of the tension chain 4 in the direction of the needles 3. Therefore, the true velocity of the tension chain 4 is greater than the true velocity of tension chain 6 in order for the component of the tension chain velocity in the direction of the needles 3 to be the same as the velocity of the thread guide6. I

This relationship can be expressed mathmatically wherein the velocity of the thread guide chain is illustrated,as Vg and the velocity of the tension chain is illustrat'e'd as Va. The velocity of the threads 5 between the guide 6 and the tension chain ,4 is illustrated as Vtl. The velocity of the threads 5 after they have been picked up by chains 1 and 2 is illustrated as Vt2. In order for tension chain 4 to draw weft thread 5 out of thread guide 6 at an angle of substantially 90 with respect to guide 6, it is necessary that the thread in the thread guide 6 be travelling at substantially the same speed as the thread attached to the tension chain 4 in the direction of the needles 3. Since. the velocity of the chain Va is the sum of its vector components Vcl and Vc2, therefore it isnece ssarilly obvious that Vcl must equal Vg. (i.e. Vg Vcl). Because Vc is the resultant of two perpendicular ,factors V cl and Vc2, therefore the speed of the tension chain Vc must be greater than the speed of the thread guide chain Vg. According to this. illustration, the speed of the thread guide chain Vg is equal to the approach velocity Vtl of the threads 5 towards the chains 1 and 2. In practice,- the velocity of approach of the threads. 5 herein described as Vtl may be equal to the velocity V12 with which chains 1 and 2 deliver the thread 5 to the needles 3. However, this need not necessarily be the exact relationship. Note also that the relative angle Agc between thread guide 6 and tension chain 4 corresponds to the angle subtended between vector Vc and vector Vg. According to that illustration, the greater the angle Agc is the faster velocity Vc must be in .order that component Vcl equals V In addition to reducing thread abrasion, the present invention allows the user to employ a shorter figure 8 type of thread guide than has heretofore been associated with warp knitting machines. Prior art uses of figure ,8 thread guides have required guides with lengths in the order of 20 feet in order to span the width of the machine. (See FIG. ,3). However, according to the present embodiment, the length of the figure 8 thread guide can be considerably shorter since it does not have to span the entire width of the machine.

While the present invention has been described with reference to a particular preferred embodiment thereof, it will be understood by those of ordinary skill in the art that modificationsmay be made without departingfrom the.spirit and scope of the invention.

I claim: I

i. impwvedflfeftinfsertihg,appa ratusforuse with a warpkri-itting'r'riachine comprisingf a plurality of .weft thread supplying spools;

a flexible band type' ofth read guide means for moveably guiding of saidlth'reads, sai d threads passing through saidthread de'mean si an endless weft te n'sipni means for taking said threads from said guide r'neajns arid drawing them 4. The apparatus of claim 1 wherein said tensioning means includes an endless chain having means thereon for gripping said threads.

5. The apparatus of claim 4 wherein the angle of the direction of travel of the endless chain of said tensioning means relative to the direction of travel of the flexible band of said guide means is such that said tensioning means draws said threads out of said guide means at an angle of approximately with respect to the direction of travel of the flexible band of said guide means. l 

1. An improved weft inserting apparatus for use with a warp knitting machine comprising: a plurality of weft thread supplying spools; a flexible band type of thread guide means for moveably guiding of said threads, said threads passing through said thread guide means; an endless weft tensioning means for taking said threads from said guide means and drawing them away therefrom; and, a first and second endless band means for taking each individual thRead from said thread guide means and said tensioning means respectively and presenting said threads to said warp knitting machine.
 2. The apparatus of claim 1 wherein said thread guide means comprises the type including and endless chain, said endless chain being in the form of a figure ''''8''''.
 3. The apparatus of claim 1 wherein said thread guide means comprises the type including a pair of endless chains placed together in the form of a figure ''''8''''.
 4. The apparatus of claim 1 wherein said tensioning means includes an endless chain having means thereon for gripping said threads.
 5. The apparatus of claim 4 wherein the angle of the direction of travel of the endless chain of said tensioning means relative to the direction of travel of the flexible band of said guide means is such that said tensioning means draws said threads out of said guide means at an angle of approximately 90* with respect to the direction of travel of the flexible band of said guide means. 